Recycled heat

Waste heat produced by the electricity generation process could be used to warm UK homes and businesses.

The technique, known as combined heat and power (CHP), is currently being studied by Southampton University researchers who believe it could be one way for the UK to cut energy consumption and carbon emissions.

The researchers contributed to a report released today by the Institution of Civil Engineers (ICE) that shows heat production accounted for 49 per cent of all primary energy consumed in the UK. This, they say, is far more than in the production of electricity or that used in the transport sector.

Southampton researcher and civil engineer Patrick James said that a coal-fired power plant such as Kingsnorth in Kent could be retrofitted with technology that captures waste heat and pipes it to local residents via district heating systems.

The Southampton research estimates that the cluster of coal-fired power stations at Kingsnorth wasted 6.55TWh of heat, and heat demand in the local area is 5.91TWh.

The report claimed a new 2,000MW carbon-capture ready coal-fired power station proposed at Kingsnorth, due to open in 2012, would address any potential heat shortfall.

ICE recommended that the government should carry out a feasibility study into heat capture and the creation of district heating networks at Drax, Ferrybridge and Eggborough in Yorkshire and Kingsnorth.

It was also suggested that the government consider the idea of building new housing developments with small-scale combined heat and power (CHP) plants.

Those smaller plants would be better at meeting the unique heating and electricity demands of a particular area, said Keith Tovey, a member of the ICE and an environmental science researcher at the University of East Anglia (UEA).

‘If you look at Denmark, each small city has its own small power station which is then more ideally located for providing combined heat and power,’ he added.

The location of a plant is a key factor because any heat produced from it will need to be piped to residents through an extensive and costly network. James said this is why many nuclear stations would not be ideal candidates for combined heat and power because those plants are usually remote and too far from any significant population.

James added that installing heat recovery systems on all centralised power plants could meet five per cent of the UK’s demand for heat and cut carbon dioxide emissions by 10 million tonnes.

The smaller-scale plants also have the potential to make a large difference in emissions, said Tovey. A small-scale CHP plant installed at the University of East Anglia reportedly cut its carbon emissions by 33 per cent.

‘We talk about emission targets and reducing carbon dioxide, but we are never going to achieve this unless we really tackle heat in a sensible way,’ he said. ‘We must reduce the demand for heat by insulating our homes, and that’s a relatively easy task for new build, but it’s a much more difficult task for the old properties. It will be easier in old properties to provide waste heat from coal stations.’

ICE hopes the government will make heat-capture assessments a part of planning conditions for all new power plants. Tovey said creating pipework between existing power stations and local residents will be a major engineering challenge, but new housing developments with nearby small-scale CHP plants could be possible by 2020.

Siobhan Wagner